Method and system for device positioning utilizing distributed transceivers with array processing

ABSTRACT

A mobile device receives signals from base stations each with multiple distributed transceivers. Each distributed transceiver may operate at different carrier frequencies. Each distributed transceiver is equipped with an independently configurable antenna array handling transmissions of the radio frequency signals to the mobile device. The mobile device generates channel measurements for the received signals, and subsequently receives a position estimate from a remote location server. The location server determines corresponding transmit diversity configurations applied to the base stations for conducting the channel measurements for the mobile device, and channel measurements at scanned locations in a location scanning region. The location server selects and utilize a signature function to calculate the position estimate for the mobile device over the transmit diversity configurations. A multi-level positioning process may be performed by adopting various signature functions, subsets of transmit configurations and/or subspaces of the location scanning region for accurate device positioning.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application makes reference to:

-   U.S. application Ser. No. 12/852,443 filed on Aug. 10, 2010; and-   U.S. Application Ser. No. 61/224,347 filed on Jul. 9, 2009.

Each of the above stated applications is hereby incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to signal processing forcommunication systems. More specifically, certain embodiments of theinvention relate to a method and system for device positioning utilizingdistributed transceivers with array processing and database processing.

BACKGROUND OF THE INVENTION

Location based services (LBSs) are emerging as a value-added serviceprovided by mobile communication network. LBSs are mobile services inwhich the user location information is used in order to enable variousLBS applications such as, for example, enhanced 911 (E-911) services. Aposition of a mobile device is determined in different ways such as, forexample, using network-based technology, using terminal-basedtechnology, and/or using hybrid technology (a combination of the formertechnologies). Many positioning technologies such as, for example, Cellof Origin (COO), Time of Arrival (TOA), Observed Time Difference ofArrival (OTDOA), Enhanced Observed Time Difference (E-OTD) as well asthe satellite-based systems such as the global positioning system (GPS),or Assisted-GPS (A-GPS), are in place to estimate the location of themobile device and convert it into a meaningful X, Y coordinate for LBSapplications.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A method and/or system for device positioning utilizing distributedtransceivers with array processing and database processing,substantially as shown in and/or described in connection with at leastone of the figures, as set forth more completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary communication system thatsupports device positioning utilizing distributed transceivers witharray processing, in accordance with an embodiment of the invention.

FIG. 2 shows a typical usage scenario where three radio sites each withmultiple distributed transceivers are utilized to estimate the positionof a mobile device, in accordance with an embodiment of the invention.

FIG. 3 is a diagram illustrating an exemplary base station that utilizesmultiple distributed transceivers with array processing for devicepositioning, in accordance with an embodiment of the invention.

FIG. 4 is a diagram illustrating an exemplary mobile device that islocated utilizing a collection of distributed transceivers with arrayprocessing, in accordance with an embodiment of the invention.

FIG. 5 is a diagram illustrating an exemplary location server thatperforms device positioning utilizing a signature-based positioningdatabase, in accordance with an embodiment of the invention.

FIG. 6 is a diagram illustrating exemplary steps utilized by a locationserver to perform device positioning utilizing distributed transceiverswith array processing, in accordance with an embodiment of theinvention.

FIG. 7 is a diagram illustrating exemplary steps utilized by a locationserver to perform multi-level device positioning utilizing a subset ofchannel transmit diversity configurations, in accordance with anembodiment of the invention.

FIG. 8 is a diagram illustrating exemplary steps utilized by a locationserver to perform multi-level device positioning over a subset of alocation scanning region, in accordance with an embodiment of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor device positioning utilizing distributed transceivers with arrayprocessing and database processing. In accordance with various exemplaryembodiments of the invention, a mobile device in a multipath environmentmay be operable to receive direct line of sight and multipath radiofrequency signals from one or more base stations each with multipledistributed transceivers. Each of the distributed transceivers mayoperate at different carrier frequencies. Each of the distributedtransceivers may be equipped with an independently configurable antennaarray handling transmissions or receptions of the radio frequencysignals to/from the mobile device. In one embodiment, the distributedtransceivers transmit a waveform and the mobile device performs thereception and propagation channel estimation. In another embodiment, themobile device may transmit a waveform and each of the distributedtransceivers may perform respective channel estimations. The mobiledevice may process the received signals to generate channel measurementsfor the received signals. A remote location server may be operable tolocate the mobile device utilizing the channel measurements for themobile device. In this regard, corresponding transmit diversityconfigurations may be determined by the location server. Thecorresponding transmit diversity configurations may be applied to thebase stations for conducting the channel measurements for the mobiledevice, and channel measurements at each scanned location in a locationscanning region. The location server may calculate the position estimatefor the mobile device over the location scanning region utilizing thechannel measurements for the mobile device, the channel measurements atscanned locations, and corresponding transmit diversity configurations.A signature function for the channel measurements over the correspondingtransmit diversity configurations may be selected by the locationserver. The location server may utilize the signature function tocalculate the position estimate for the mobile device over the transmitdiversity configurations. Depending on resolution of the signaturefunction over the scanned locations in the location scanning region, amulti-level positioning process may be performed for highly accuratepositioning. In this regard, the location server may utilize a differentsignature function, a subset of transmit configurations and/or asubspace of the location scanning region to update the position estimatefor the mobile device.

FIG. 1 is a diagram illustrating an exemplary communication system thatsupports device positioning utilizing distributed transceivers witharray processing, in accordance with an embodiment of the invention.Referring to FIG. 1, there is shown a communication system 100. Thecommunication system 100 comprises a plurality of multi-radio mobiledevices, of which multi-radio mobile devices 112-116 are illustrated, aheterogeneous network system 120, a Global Navigation Satellite Systems(GNSS) satellite infrastructure 130, and a location server 140comprising a reference database 142. The heterogeneous network system120 comprises a plurality of different radio access networks, of which aWLAN network 121, a Bluetooth network 122, a CDMA network 123, a UMTSnetwork 124, a WiMAX network 125, and millimeter wave networks 126 areillustrated.

The multi-radio mobile devices 112-116 may comprise suitable logic,circuitry, interfaces and/or code that are operable to communicate radiofrequency signals with a plurality of mobile communication networks suchas, for example, the WLAN network 121, the Bluetooth network 122, theCDMA network 123, the UMTS network 124, the WiMAX network 125, and/orthe mmWave networks 126. Depending on device capabilities and userpreferences, a multi-radio mobile device such as the multi-radio mobiledevice 112 may utilize or enable one or more radios such as a WLAN radioand a cellular radio to communicate with radio sites in radio accessnetworks to receive signals of a desired service. Radio sites, as usedherein, of a specific radio access network may comprise one or more basestations or access points. Radios such as a millimeter Wave (mmWave), aWLAN, WiMax, Bluetooth, Bluetooth Low Energy (BLE), or other types ofradios may be utilized to receive radio frequency signals for thedesired service over radio channels. In this regard, radios such asmmWave radios may be utilized at very high carrier frequencies for highthroughput wireless communications. For example, various standardsorganization such as, for example, the 60 GHz wireless standard,WirelessHD, WiGig, and WiFi IEEE 802.11ad, are using high frequenciessuch as the 60 GHz frequency spectrum for high throughput wirelesscommunications. The 60 GHz spectrum band may also be used for unlicensedshort-range data links such as 1.7 km with data throughputs up to 6Gbits/s.

In mobile communication, a radio channel may be characterized bymultipath reception, which refers to receiving not only directline-of-sight (LOS) radio waves, but also a number of reflected radiowaves, that is non-LOS radio waves. With multi-radio capability, themulti-radio mobile device 112 may be operable to receive signals from aset of radio sites such as the base stations 123 a and the WLAN AP 121a. In an embodiment of the invention, the multi-radio mobile device 112may be operable to perform both non-LOS measurements and LOSmeasurements over signals received from a selected radio site such asthe base station 123 a. Depending on device capabilities, themulti-radio mobile device 112 may be configured to derive or determinepropagation channel responses or received signal strength indicators(RSSIs) utilizing the LOS measurements and the non-LOS measurements forthe received signals.

In an embodiment of the invention, the multi-radio mobile device 112 maybe operable to create or form channel measurements for correspondingsignals received from selected radio sites such as the base station 123a. In this regard, the channel measurements for the signals receivedfrom the base station 123 a may be either the propagation channelresponses or RSSIs. In instances where the base station 123 a isutilized to determine or estimate the position for the multi-radiomobile device 112, the corresponding channel measurements may beuploaded or communicated to the location server 140 via theheterogeneous network system 120. For example, the uploaded channelmeasurements may be combined over multiple transceivers of the basestation 123 a to create a channel signature with higher channelresolution characteristic. A so-called channel signature is referred toas a channel transfer function or simply a channel. U.S. applicationSer. No. 12/852,443 filed on Aug. 10, 2010, provides detaileddescriptions relates to identifying or determining channelcharacteristics for received signals at a given location utilizingvarious means, each of which is hereby incorporated herein by referencein its entirety.

In other embodiments a mobile device such as the mobile device 116 maybe operable to locate itself. For example, the mobile device 116 mayreceive its position from the location server 140 or computes itsposition itself. The mobile device 116 then may act as a moving basestation and may generate channel estimations at its position for othermobile devices such as mobile device 112.

The heterogeneous network system 120 may comprise suitable devices,circuitry, interfaces and/or code that are operable to provide radioconnections between a wireless mobile device such as the multi-radiomobile device 112 and appropriate wireless radio communication networks.Different radio access technologies may be utilized in the heterogeneousnetwork system 120 to provide the multi-radio mobile device 112 with anaccess to a desired service.

The WLAN network 121 may comprise suitable devices, circuitry,interfaces and/or code that are operable to provide data services towireless LAN enabled communication devices such as the multi-radiomobile device 112 using wireless LAN technology. Exemplary wireless LANtechnology may comprise, for example, IEEE Standard 802.11, 802.11a,802.11b, 802.11d, 802.11e, 802.11g, 802.11n, 802.11ac, 802.11v, and/or802.11u. The WLAN network 121 comprises a plurality of WLAN accesspoints such as WLAN access points (APs) 121 a through 121 c. The WLANnetwork 121 may be operable to communicate various data services such asa location-based service (LBS) over WLAN connections between the WLANAPs 121 a through 121 c and corresponding WLAN capable devices such as,for example, the multi-radio mobile device 112. In this regard, the WLANAPs 121 a through 121 c each may utilize multiple distributedtransceivers to communicate with the multi-radio mobile device 112 overthe WLAN connections. Transceivers of the WLAN AP 121 a, for example,may be configured as distributed transceiver architecture. Eachdistributed transceiver for the WLAN APs 121 a may be equipped with anantenna array. In this regard, each antenna array for the WLAN AP 121 amay be independently configured at a different and sufficientlyuncorrelated direction to create several independent antenna arrays foraccurately positioning of the multi-radio mobile device 112.

The Bluetooth network 122 may comprise suitable devices, circuitry,interfaces and/or code that are operable to provide data services tovarious Bluetooth enabled mobile devices such as the multi-radio mobiledevice 112 using Bluetooth technology. Exemplary Bluetooth technologymay comprise, for example, IEEE Standard IEEE 802.15 WPAN and/or IEEE802.15.4. Other PAN technology such as Bluetooth Low Energy (BLE) andZigBee may also be utilized without deviating from the spirit and scopeof the invention. The Bluetooth network 122 comprises a plurality ofBluetooth access points such as Bluetooth access points 122 a through122 c. The Bluetooth network 122 may be operable to communicate variousdata services such as a location-based service (LBS) over Bluetoothconnections between, for example, the multi-radio mobile device 112 anda Bluetooth access point (AP) such as the Bluetooth AP 122 a. In thisregard, the Bluetooth APs 122 a through 122 c may each utilize multipledistributed transceivers to communicate with the multi-radio mobiledevice 112 over the Bluetooth connections. Transceivers of the BluetoothAP 122 a, for example, may be configured as distributed transceiverarchitecture. Each distributed transceiver for the Bluetooth APs 122 amay be equipped with an antenna array. In this regard, each antennaarray for the Bluetooth AP 122 a may be independently configured at adifferent and sufficiently uncorrelated direction to create severalindependent antenna arrays for accurately positioning of the multi-radiomobile device 112.

The CDMA network 123 may comprise suitable devices, circuitry,interfaces and/or code that are operable to provide data services tovarious CDMA enabled mobile devices such as the multi-radio mobiledevice 112 using CDMA technology or variants thereof, for example,WCDMA. The CDMA network 123 comprises a plurality of base stations suchas base stations 123 a through 123 b. The CDMA network 123 may beoperable to communicate various data services such as a location-basedservice (LBS) over CDMA connections between, for example, themulti-radio mobile device 112 and a CDMA base station such as the basestation 123 a. In this regard, the base stations 123 a through 123 beach may utilize multiple distributed transceivers to communicate withthe multi-radio mobile device 112 over the CDMA connections.Transceivers of the base station 123 a, for example, may be configuredas distributed transceiver architecture. Each distributed transceiverfor the base station 123 a may be equipped with an antenna array. Inthis regard, each antenna array for the base station 123 a may beindependently configured at a different and sufficiently uncorrelateddirection to create several independent antenna arrays for accuratelypositioning of the multi-radio mobile device 112.

The UMTS network 124 may comprise suitable devices, circuitry,interfaces and/or code that are operable to provide data services tovarious UMTS enabled mobile devices such as the multi-radio mobiledevice 112 using UMTS technology. The UMTS network 124 comprises aplurality of base stations such as base stations 124 a through 124 b.The UMTS network 124 may be operable to communicate various dataservices such as a location-based service (LBS) over UMTS connectionsbetween, for example, the multi-radio mobile device 112 and a UMTS basestation such as the base station 124 a. In this regard, the basestations 124 a through 124 b each may utilize multiple distributedtransceivers to communicate with the multi-radio mobile device 112 overthe UMTS connections. Transceivers of the base station 124 a, forexample, may be configured as distributed transceiver architecture. Eachdistributed transceiver for the base station 124 a may be equipped withan antenna array. In this regard, each antenna array for the basestation 124 a may be independently configured at a different andsufficiently uncorrelated direction to create several independentantenna arrays for accurately positioning of the multi-radio mobiledevice 112.

The WiMAX network 125 may comprise suitable devices, circuitry,interfaces and/or code that are operable to provide data services tovarious WiMAX enabled mobile devices such as the multi-radio mobiledevice 112 using WiMAX technology. The WiMAX network 125 comprises aplurality of WiMAX base stations such as base stations 125 a through 125b. The WiMAX network 125 may be operable to communicate various dataservices such as a location-based service (LBS) over WiMAX connectionsbetween, for example, the multi-radio mobile device 112 and a WiMAX basestation such as the base station 125 a. In this regard, the basestations 125 a through 125 b may utilize each multiple distributedtransceivers to communicate with the multi-radio mobile device 112 overthe WiMAX connections. Transceivers of the base station 125 a, forexample, may be configured as distributed transceiver architecture. Eachdistributed transceiver for the base station 125 a may be equipped withan antenna array. In this regard, each antenna array for the basestation 125 a may be independently configured at a different andsufficiently uncorrelated direction to create several independentantenna arrays for accurately positioning of the multi-radio mobiledevice 112.

The millimeter wave networks 126, which may operate at the 60 GHzcarrier frequency, may be used due to their efficient beamformingcharacteristics by using configurable antenna arrays and smaller size ofantennas, and antenna arrays for the 60 GHz frequency range. The mmWavenetworks 126 may be implemented utilize wireless technology as definedin WiGig or IEEE 802.11ad standards. The mmWave networks 126 maycomprise devices capable of operating according to the 60 GHz standardsWiGig or IEEE 802.11ad or a proprietary non-standard 60 GHz protocoldesigned and optimized for positioning applications. Furthermore, basestations 126 a and 126 b in the millimeter wave networks 126 may deploymultiple transceivers each with a configurable or fixed antenna pattern.

The GNSS satellites 132 through 136 may comprise suitable logic,circuitry and/or code that may be operable to generate and broadcastsatellite navigational information in suitable radio-frequency (RF)signals to various GNSS capable communication devices such as themulti-radio mobile device 114. The broadcast satellite navigationalinformation may be utilized to determine the position for themulti-radio mobile device 114. In an embodiment of the invention, thedetermined position for the multi-radio mobile device 114 together withchannel measurements available at the multi-radio mobile device 114 maybe uploaded or communicated to the location server 140 for higherpositioning resolution.

The location server 140 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to receive channelmeasurements from a plurality of users such as radio sites and/or mobiledevices in the heterogeneous network system 120. The received channelmeasurements may comprise propagation channel responses or RSSIs, and/orlocations where the channel measurements are actually captured ordetected.

The location server 140 may be operable to collect and/or retrievechannel measurements to build the positioning database 142. For a basestation that is selected and utilized to determine or estimate theposition for the multi-radio mobile device 112, the location server 140may combine the collected channel measurements over the transceivers ofthe selected base station, thereby creating a channel with higherresolution characteristic for the selected base station. The locationserver 140 may utilize channel signatures of selected base stations toestimate or determine the position for the multi-radio mobile device112. The location server 140 may provide the determined position via theheterogeneous network system 120 to the multi-radio mobile device 112 tosupport LBSs.

Although location server 140 is illustrated in FIG. 1 for wirelesslylocate a mobile device utilizing channel measurements for the mobiledevice, the invention may not be so limited. Accordingly, one or morebase stations with sufficient data processing capacity may be operableto locate the mobile device utilizing the channel measurements for themobile device without departing from the spirit and scope of variousembodiments of the invention.

In an exemplary operation, a device such as the multi-radio mobiledevice 114 may be operable to receive radio frequency signals from basestations such as the base stations 123 a and the WLAN AP 121 a. Eachselected base station may be configured to utilize multiple distributedtransceivers for communication with the multi-radio mobile device 114.Each distributed transceiver for the selected base station may beequipped with an independently configurable antenna array that isoperable to provide highly accurate device positioning. Channelmeasurements such as propagation channel responses or RSSIs may bedetermined utilizing the LOS measurements and the non-LOS measurementsfor the received signals from the selected radio site. The channelmeasurements may be uploaded or communicated to the location server 140via the heterogeneous network system 120. In certain instances, a basestation may be selected and utilized to determine the position for themulti-radio mobile device 114. In this regard, the location server 140may be operable to combine the channel measurements over thetransceivers of the selected base station to create a channel signatureor transfer function with higher channel resolution characteristic. Thechannel signature of the selected base station may be utilized toestimate or determine the position for the multi-radio mobile device114. The location server 140 may provide the position estimate to themulti-radio mobile device 114 to support LBSs.

FIG. 2 shows a typical usage scenario where three radio sites each withmultiple distributed transceivers are utilized to estimate the positionof a mobile device, in accordance with an embodiment of the invention.As shown, three base stations 222, 224, and 226 each with multipledistributed transceivers may be utilized to estimate or determine theposition of a mobile device 210. Each distributed transceiver for thebase stations 222, 224, and 226 may be equipped with an independentlyconfigurable antenna array for highly accurate device positioning. Forexample, antenna arrays 222 a and 222 b, antenna arrays 224 a and 224 b,and antenna arrays 226 a and 226 b, are incorporated with the basestations 222, 224, and 226, respectively. In this regard, the antennaarrays 222 a and 222 b, 224 a and 224 b, and 226 a and 226 b may becoordinated and may be arranged at a different and sufficientlyuncorrelated direction to create several independent antenna arrays foraccurate positioning of the mobile device 210.

The mobile device 210 may comprise a cell phone, laptop, tabletcomputer, PDA, wireless headset, pager, digital/video camera, toy,electronic book reader, and/or CD/DVD/cassette/MP-3 players. In someembodiments, the mobile device 210 may be a battery-less tag thatreceives wireless power through a wireless charger during the shortperiods of signal reception and channel estimation. The mobile device210 may comprise multiple radios utilized to receive radio signals fromthe base stations 222, 224, and 226. The mobile device 210 may comprisemultiple transceivers each with an antenna array to receive radiosignals from the base stations. In other embodiments the mobile device210 may deploy distributed transceiver structure as well. In this casethe channel measurements to one or all of transceivers within the mobiledevice 210 may be used for position matching. All or only the mostsuitable transceiver within the mobile device 210 may be selected forpositioning. If the transceivers within the mobile device 210 deployantenna arrays as well, then the device's orientation data, from anembedded compass, gyroscope, etc., for example, may take into accountdevice's orientation in correlation channel measurements. Withreflections from surrounding objects such as, for example, multipathreflectors 241 through 245, the mobile device 210 may be operable toreceive direct LOS radio waves over direct paths as well as reflected(multipath) radio waves wave (non-LOS radio waves) over multipaths. Forexample, the mobile device 210 placed at position 1 with coordinates of(x, y, z) may receive two direct LOS radio waves 232 and 233 from thebase station 222 and the base station 224, and four multipath radiowaves 231 a, 234 a, 235 a, and 236 a caused by reflections fromobstacles, the multipath reflectors 241 through 244, respectively.

The reflectors 241-244 in FIG. 2 may be random natural reflectors in theenvironment that are exploited by the system for improved positioning.In another embodiment, high efficiency passive and/or active reflectorsare installed in the environment for stronger and controlled multipathsfor better positioning accuracy. In some embodiments, the installedreflectors' locations with respect to base stations are known andexploited for positioning. This positioning method, however, may be alsoapplicable to situations where there are no reflectors present, becausethe channel measurements for the received signals are determined for LOSmeasurements as well as non-LOS measurements. In situations where theenvironment does not produce multipaths, however, time-delaytriangulation positioning methods may also be used as an alternative,such as that described in “Method and system for determining theposition of a mobile station”, Mehran Moshfeghi, U.S. Application Ser.No. 61/224,347 filed on Jul. 9, 2009.

FIG. 3 is a diagram illustrating an exemplary base station that utilizesmultiple distributed transceivers with array processing for devicepositioning, in accordance with an embodiment of the invention.Referring to FIG. 3, there is shown a base station 300. The base station300 comprises a plurality of transceivers 311 ₁, 311 ₂, . . . , 311_(N), a processor 320, a channel measurement database 330, and a memory340.

The transceivers 311 ₁, 311 ₂, . . . , 311 _(N) may comprise suitablelogic, circuitry, interfaces and/or code that may be operable to receiveand/or transmit radio frequency signals from and/or to the multi-radiomobile devices 112-116 using air interface protocols specified in, forexample, UMTS, GSM, LTE, WLAN, 60 GHz/mmWave, and/or WiMAX. Thetransceivers 311 ₁, 311 ₂, . . . , 311 _(N) may be configured asdistributed transceiver architecture. Each of the distributedtransceivers 311 ₁, 311 ₂, . . . , 311 _(N) may be equipped with aprogrammable antenna array or fixed directional antenna. For example,antenna arrays 310 ₁, 310 ₂, . . . , 310 _(N) are incorporated with thedistributed transceivers 311 ₁, 311 ₂, . . . , 311 _(N), respectively.The antenna arrays may be utilized for transmitting and/or receivingsignals.

The antenna arrays 310 ₁, 310 ₂, . . . , 310 _(N) may comprise suitablelogic, circuitry, interfaces and/or code that may be operable togenerate antenna beam patterns to form a plurality of beams. Theplurality of beams may be arranged to orient in specific directions suchas a direction towards an intended mobile device to be located. In anembodiment of the invention, each of the antenna arrays 310 ₁, 310 ₂, .. . , 310 _(N) may be configured to utilize different antenna patternsand array configurations. For example, antenna patterns of the antennaarray 310 ₁ may be arranged by adjusting phase array coefficients forthe distributed transceiver 311 ₁. In this regard, each of the antennaarrays 310 ₁, 310 ₂, . . . , 310 _(N) may be arranged at a different andsufficiently uncorrelated direction so as to create several independentantenna arrays for accurate positioning of an intended device such asthe multi-radio mobile device 112. In an embodiment of the invention,each of the antenna arrays 310 ₁, 310 ₂, . . . , 310 _(N) may beconfigured to be linear, planar, circular or hexagonal arrays so as tocover reflections in the multipath environment between the base station300 and the multi-radio mobile device 112. In addition, the antennaarrays 310 ₁, 310 ₂, . . . , 310 _(N) may be arranged or configured tooperate at different carrier frequencies f₁, . . . , f_(K). The numberof transceivers N, and number of carrier frequencies K, may varydepending on device capability and available resources. In general, thecarrier frequencies f₁, . . . , f_(K) may include a few frequencies inthe 900 MHz band such as Bluetooth, a few in the 2.4 GH/5 GHz band suchas WLAN, and a few in the 60 GHz band such as mmWave.

The processor 320 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to manage and/or control operations ofassociated device components such as the distributed transceivers 311 ₁,311 ₂, . . . , 311 _(N). The processor may generate training or pilotsignals in the case that channel estimations may be performed at themobile device. The processor 320 may perform the channel estimation inthe case that the mobile device transmits the signal. The processor 320may compile and analyze the database of collected measurements duringscanning for partitioning them based on signature functions andachievable resolutions. The processor 320 may receive channelmeasurements reported from the multi-radio mobile device 112, forexample. The received channel measurements may comprise channel qualityinformation such as propagation channel responses, RSSIs or channelquality indicator (CQI) derived or captured at the multi-radio mobiledevice 112. The processor 320 may store the received channelmeasurements into the channel measurement database 330. In an embodimentof the invention, the processor 320 may configure and/or adjust phasearray coefficients w_(i), i=1, . . . , N, for each of the distributedtransceivers 311 ₁, 311 ₂, . . . , 311 _(N) based on channel qualityinformation provided from the multi-radio mobile device 112. Each w_(i),i=1, . . . , N represents a vector that comprises the antennacoefficients used for each distributed transceiver. In this regard, theprocessor 320 may be operable to arrange or deploy the phase arraycoefficients w_(i), i=1, . . . , N, to span and cover reflections in themultipath environment that create reasonably strong multipaths betweenthe base station 300 and the multi-radio mobile device 112. In anembodiment of the invention, the processor 320 may determine or selectwhich of the distributed transceivers 311 ₁, 311 ₂, . . . , 311 _(N) maybe activated for transmissions to the multi-radio mobile device 112. Theprocessor 320 may place the activated distributed transceivers 311 ₁,311 ₂, . . . , 311 _(N) to operate at different frequencies f₁, . . . ,f_(K) for transmissions to the multi-radio mobile device 112.

The channel measurement database 330 may comprise suitable logic,circuitry, interfaces and/or code that may be operable to store channelmeasurements supplied from associated mobile devices such as the mobiledevices 112-116. The stored channel measurements may be utilized toconfigure or adjust the distributed transceivers 311 ₁, 311 ₂, . . . ,311 _(N) to various antenna patterns and array configurations. Thechannel measurement database 330 may be operable to manage and updatethe stored channel measurements whenever necessary. The updates mayoccur aperiodically or periodically. For example, the channelmeasurement database 330 may be utilized to refine the stored channelmeasurements based on information on corresponding antenna patterns andtransmit array configurations.

The memory 340 may comprise suitable logic, circuitry, interfaces and/orcode that may be operable to store information such as executableinstructions and data that may be utilized by the processor 320 and/orother associated component units such as, for example, the referencedatabase 330. The memory 340 may comprise RAM, ROM, low latencynonvolatile memory such as flash memory and/or other suitable electronicdata storage.

In an exemplary operation, the processor 320 may be operable to controloperations of, for example, the distributed transceivers 311 ₁, 311 ₂, .. . , 311 _(N). The processor 320 may receive or collect channelmeasurements from users such as the multi-radio mobile device 112. Phasearray coefficients w₁, i=1, . . . , N, for each of the distributedtransceivers 311 ₁, 311 ₂, . . . , 311 _(N) may be configured oradjusted based on the channel measurements provided from the multi-radiomobile device 112. In this regard, the phase array coefficients w_(i),i=1, . . . , N, may be arranged to span and cover reflections in themultipath environment between the base station 300 and the multi-radiomobile device 112. The distributed transceivers 311 ₁, 311 ₂, . . . ,311 _(N) may be selectively activated for transmissions or receptions,at different frequencies f₁, . . . , f_(K), for example, to themulti-radio mobile device 112 based on the channel measurements providedfrom the multi-radio mobile device 112.

FIG. 4 is a diagram illustrating an exemplary mobile device that islocated utilizing a collection of distributed transceivers with arrayprocessing, in accordance with an embodiment of the invention. Referringto FIG. 4, there is shown a multi-radio mobile device 400. Themulti-radio mobile device 400 comprises a GNSS radio 402, a WLAN radio404, a Bluetooth radio 406, a cellular radio 408, a WiMAX radio 410, a60 GHz radio 411, a local multipath database 412, a wireless powerreceiver unit 413, an orientation finding unit 415, a host processor 414and a memory 416.

The GNSS radio 402 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to detect and receive GNSS signals froma plurality of visible GNSS satellites such as the GNSS satellite132-136. The GNSS radio 402 may be operable to utilize the received GNSSsignals to calculate or determine navigation information such as a GNSSposition and/or a velocity of the GNSS radio 402. The calculated GNSSposition of the GNSS radio 402 may be provided to the host processor414, where it may be utilized to support location-based services. Ininstances where other radios such as the WLAN radio 404 and the cellularradio 408, for example, are receiving corresponding RF signals at thecalculated GNSS position of the GNSS radio 402, or at a known location,channel measurements for the received RF signals over the WLAN radio 404and the cellular radio 408 may be location stamped utilizing thecalculated GNSS position of the GNSS radio 402, or utilizing the knownlocation.

The WLAN radio 404 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to receive and/or transmit radiofrequency signals using wireless LAN technology. The WLAN radio 404 maybe operable to transmit and/or receive radio frequency (RF) signals overWLAN connections between the multi-radio mobile device 400 and a WLAN APsuch as the WLAN AP 121 a. In instances where the WLAN radio 404, at thecalculated GNSS position of the GNSS radio 402, or at a known location,is receiving RF signals from the WLAN AP 121 a, channel measurements forthe received RF signals over the WLAN radio 404 may be location stampedutilizing the calculated GNSS position of the GNSS radio 402, orutilizing the known location.

The Bluetooth radio 406 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to receive and/or transmitradio frequency signals using Bluetooth technology. The Bluetooth radio406 may be operable to transmit and/or receive radio frequency (RF)signals over Bluetooth connections between the multi-radio mobile device400 and a Bluetooth AP such as the Bluetooth AP 122 a. In instanceswhere the Bluetooth radio 406, at the calculated GNSS position of theGNSS radio 402, or at a known location, is receiving RF signals from theBluetooth AP 122 a, channel measurements for the received RF signalsover the Bluetooth radio 406 may be location stamped utilizing thecalculated GNSS position of the GNSS radio 402, or utilizing the knownlocation.

The cellular radio 408 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to receive and/or transmitradio frequency signals using various cellular technologies such as, forexample, CDMA, UMTS, GSM and/or LTE. The cellular radio 408 may beoperable to transmit and/or receive radio frequency (RF) signals overcellular radio connections between the multi-radio mobile device 400 anda cellular base station such as the base station 123 a in the CDMAnetwork 123. In instances where the cellular radio 408, at thecalculated GNSS position of the GNSS radio 402, or at a known location,is receiving RF signals from the base station 123 a, channelmeasurements for the received RF signals over the cellular radio 408 maybe location stamped utilizing the calculated GNSS position of the GNSSradio 402, or utilizing the known location.

The WiMAX radio 410 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to receive and/or transmit radiofrequency signals using WiMAX technology. The WiMAX radio 410 may beoperable to transmit and/or receive radio frequency (RF) signals overWiMAX radio connections between the multi-radio mobile device 400 and aWiMAX base station such as the base station 125 a in the WiMAX network125. In instances where the WiMAX radio 410, at the calculated GNSSposition of the GNSS radio 402, or at a known location, is receiving RFsignals from the base station 125 a, channel measurements for thereceived RF signals over the WiMAX radio 410 may be location stampedutilizing the calculated GNSS position of the GNSS radio 402, orutilizing the known location.

The 60 GHz radio 411 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to receive and/or transmit radiofrequency signals in a 60 GHz frequency band.

The local channel measurement database 412 may comprise suitable logic,circuitry, interfaces and/or code that may be operable to record andstore data related to local multipath environment information, which maycomprise channel measurements, channel transmit diversity settings, andlocations where the channel measurements are captured or determined. Thechannel transmit diversity settings may comprise information such asradio site identifier index, transceiver index, transceiver operatingfrequency, transmit antenna patterns and array configurations. Thechannel measurements may be characterized by channel responses (channelstrength and group delay), or RSSIs. The stored channel measurements maybe provided to the corresponding radio sites such as the base station300. The provided channel measurements may be utilized by the basestation 300 to configure the distributed transceivers 311 ₁, 311 ₂, . .. , 311 _(N), and/or to adjust phase array coefficients so as to coverreflections in the multipath environment between the base station 300and the multi-radio mobile device 400. The channel measurements withcorresponding channel transmit diversity settings may be uploaded orcommunicated to the location server 140 to build and/or refine thepositioning database 142. Content in the local channel measurementdatabase 412 may be arranged or stored in a lookup table 412 a, forexample. The local channel measurement database 412 may be updated orrefined on an as needed basis, aperiodically or periodically.

The wireless power receiver unit 413 may comprise suitable logic,circuitry, interfaces and/or code that may be operable to receive and/orcollect power transmitted from wireless power transmitters. For example,the wireless power receiver unit 413 may comprise a low power receiverwhen it is a consumer product such as a mobile phone or battery, capableof receiving no more than 5 Watt from a wireless power transmitter.

The host processor 414 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to manage, coordinate and/orcontrol operations of associated device component units such as, forexample, the GNSS radio 402, the cellular radio 408, and/or the localchannel measurement database 312, depending on usages. For example, thehost processor 414 may be operable to activate or deactivate one or moreassociated radios such as the GNSS radio 402 on an as needed basis inorder to save power. Depending on device capabilities and userpreferences, the host processor 414 may be operable to utilize or enableassociated radios such as the WLAN radio 404 and the cellular radio 408to receive signals for a desired service in a multipath environment. Inthis regard, the host processor 414 may process the received signals todetermine or measure channel characteristics such as, for example,channel response or RSSIs, for the received signals. In an embodiment ofthe invention, the host processor 414 may be operable to provide orreport channel measurements to the corresponding radio sites such as thebase station 300. The channel measurement report may be utilized by thebase station 300 to configure the distributed transceivers 311 ₁, 311 ₂and 311 _(N) and/or to adjust phase array coefficients to coverreflections in the multipath environment between the base station 300and the multi-radio mobile device 400. In an embodiment of theinvention, the host processor 414 may be operable to provide channelmeasurements from the local channel measurement database 412 to thelocation server 140 to build the positioning database 142 for higherpositioning resolution.

The orientation finding unit 415 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to identify or findorientation information for the mobile device 400. The orientationfinding unit 415 may comprise a gyroscope and/or an accelerometer.

The memory 416 may comprise suitable logic, circuitry, interfaces and/orcode that may be operable to store information such as executableinstructions and data that may be utilized by the host processor 414and/or other associated component units such as, for example, the WLANradio 404 and the Bluetooth radio 406. The memory 416 may comprise RAM,ROM, low latency nonvolatile memory such as flash memory and/or othersuitable electronic data storage.

In an exemplary operation, the host processor 414 may be operable toutilize associated radios such as the WLAN radio 404 and the WiMAX radio410 to receive radio frequency signals from radio sites such as the WLANAP 121 a and the base station 125 a, respectively. The host processor414 may process or measure the received signals to determine channelcharacteristics such as, for example, channel response or RSSIs, for thereceived signals. The host processor 414 may communicate the channelmeasurements to the corresponding radio sites such as the base station125 a to adjust channel transmit diversity settings such as theconfiguration of antenna patterns and phase array coefficients for thedistributed transceivers 311 ₁, 311 ₂ and 311 _(N). The host processor414 may provide the channel measurements to the location server 140 tobuild and/or refine the positioning database 142.

FIG. 5 is a diagram illustrating an exemplary location server thatperforms device positioning utilizing a signature-based positioningdatabase, in accordance with an embodiment of the invention. Referringto FIG. 5, there is shown a location server 500. The location server 500comprises a processor 502, a positioning database 504 and a memory 506.The location server 500 may be a remote/separate server or integratedinto one of the base stations.

The processor 502 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to manage and/or control operations ofthe positioning database 504 and the memory 506. The processor 502 maybe operable to communicate with the heterogeneous network system 120 tocollect and/or retrieve channel measurements to build the positioningdatabase 504 for device positioning. The processor 502 may comprise adatabase processing engine 503 responsible for coordination of databaseprocessing activities.

The database processing engine 503 may comprise, suitable logic,circuitry, interfaces and/or code that may be operable to handle orperform database processing for the location server 500. Assume that Mbase stations and/or APs, denoted as BS_(j), j=1, . . . , M, areselected and utilized by the location server 500 to estimate theposition (x,y,z) in a three dimensional (3D) Cartesian coordinate systemfor a device to be located, for example, the multi-radio mobile device112. The base stations BS_(j), j=1, . . . , M, may be configured toutilize a collection of N_(j) distributed transceivers i=1, . . . ,N_(j) for transmissions to the device to be located. Each of thedistributed transceivers i=1, . . . , N may be equipped with one ofindependently configurable antenna arrays, i=1, . . . , N_(j). Each ofthe distributed transceivers i=1, . . . , N_(j) may be configured tooperate at different carrier frequencies f_(k,i) ^(j)=f_(1,i) ^(j), . .. f_(K) _(j) _(,i) ^(j). Furthermore, assume w_(1,i) ^(j), . . . ,w_(S,i) ^(j) represent the phase array coefficients of the i^(th)transceiver for the base stations BS_(j), i=1, . . . , N_(j); j=1, . . ., M. The phase array coefficients of w_(s,i) ^(j), s=1, . . . , S, maycomprise a vector of a size equal to number of antenna elements deployedat the transceiver of the base station BS_(j), where S represents thetotal number of array coefficients that are used/exercised at the basestation for positioning. The set {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}, where,j=1, . . . , M; i=1, . . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), . . . ,f_(K) _(j) _(,i) ^(j); w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j),comprises various transmit diversity settings for channels from the basestations BS_(j), j=1, . . . , M, to the device to be located. The numberof transceivers N_(j) and number of carrier frequencies K_(j) availablefor each of the base stations BS_(j), j=1, . . . , M, may vary dependingon system configuration.

In an embodiment of the invention, the database processing engine 503may be operable to select or identify a location scanning region R_(s)for the device to be located. The database processing engine 503 may beoperable to scan each location (x,y,z) within the location scanningregion R_(s). Corresponding channel measurements collected at eachscanned location may be utilized to estimate the position for the deviceto be located. In telecommunication, a radio channel may becharacterized by channel strength and group delay (channel phasemeasurement). Signature-based channel measurements are referred to aschannel measurements derived from channel signatures or transferfunctions. Assume Hi represents signature-based channel measurements forthe device to be located, and H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}represents signature-based channel measurements collected at eachscanned location (x,y,z)εR_(s), where, j=1, . . . , M; i=1, . . . ,N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i) ^(j); w_(s,i)^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j). At each scanned location(x,y,z)εR_(s), the database processing engine 503 may be operable toinstruct the base stations BS_(j), j=1, . . . , M, to conduct or performmeasuring a set of H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} over the transmitdiversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} during thescanning phase. Specifically, the signature-based channel measurementsH₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} depend on scanned locations(x,y,z)εR_(s). For example, at a specific scanned location (x′, y′,z′)εR_(s), H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}_((x′,y′,z′)) corresponds toa set of channel measurements conducted over the transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}, where, j=1, . . . , M;i=1, . . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i)^(j); w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j). In someembodiments, the transceivers at each base station may be configuredaccording to the location server. Then the mobile device may perform thechannel estimations and report them back to the location server orengine. In other embodiments, the mobile device may be instructed totransmit a signal while the transceivers at each base station areconfigured according to the location server and the base stationsperform the channel estimations and report them back to the locationserver.

In an embodiment of the invention, the database processing engine 503may be operable to define and utilize a signature function SF( ) toestimate or determine the position for the device to be located, forexample, the multi-radio mobile device 112. In this regard, thesignature function SF( ) may be defined or selected as a function ofchannel measurement for the device to be located, H{j,i,f_(k,i)^(j),w_(s,i) ^(j)} and channel measurements at each previously scannedlocation, H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}, over the transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. In other words, thesignature function SF( ) may be expressed as SF(H{j,i,f_(k,i)^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}). The databaseprocessing engine 503 may calculate values of SF(H{j,i,f_(k,i)^(j),w_(s,i) ^(j)}, H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}) for measured setof H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} against each previously collectedH₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} over each scanned location in thelocation scanning region R_(s). The position estimation for the deviceto be located may be calculated or determined utilizing the followingexpression:

$\begin{matrix}{( {\hat{x},\hat{y},\hat{z}} ) = {\min\limits_{{({x,y,z})} \in R_{s}}{{SF}( {{H\{ {j,i,f_{k,i}^{j},w_{s,i}^{j}} \}},{H_{0}\{ {j,i,f_{k,i}^{j},w_{s,i}^{j}} \}}} )}}} & (1)\end{matrix}$

where, j=1, . . . , M; i=1, . . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), .. . , f_(K) _(j) _(,i) ^(j); w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i)^(j), and (x, y, z) are scanned locations within the location scanningregion R_(s). The position estimation ({circumflex over(x)},ŷ,{circumflex over (z)}) resulting in the minimum signaturefunction SF( ) is considered as the most likelihood location estimatefor the device to be located, such like the multi-radio mobile device112.

Depending on location accuracy requirements, the database processingengine 503 may be operable to coordinate with the positioning database504 so as to optimize database processing. For example, the databaseprocessing engine 503 may be operable to calculate the signaturefunction SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}), j=1, . . . , M; i=1, . . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), .. . , f_(K) _(j) _(,i) ^(j); w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i)^(j), and may repeat the calculation at possible position candidates p₁,. . . , p_(I), for the most likelihood location estimate ({circumflexover (x)},ŷ,{circumflex over (z)}) for the device to be located. In anembodiment of the invention, several different signature functions SF( )may be defined and utilized depending on accuracy requirements,availability of antenna arrays, target location acquisition time,processing power consumption, and/or multipath environment orconditions. For example, a signature function SF( ) with a sufficientlylarge gradient versus locations (x,y,z)εR_(s) may be selected orutilized for a low position estimation error. The slope of the signaturefunction SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}) versus locations (x,y,z)εR_(s) may be considered as a measure oflocation resolution capability of the signature function SF( )definition and the positioning database 504. To quantify the locationresolution and/or reliability at each (x,y,z)εR_(s) and for thesignature function SF( ) definition, the signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})in Equation (1) may be calculated by substituting H{j,i,f_(k,i)^(j),w_(s,i) ^(j)} with channel measurements at all the availablescanned locations (x,y,z)εR_(s), and using H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)} as the channel measurement set for scanned location (x₊,y₊,z₊) inthe region R_(s). The gradient of the above calculated SF( ) valuesversus the scanned locations (x,y,z)εR_(s) and around the location(x₊,y₊,z₊) may be utilized as an indication of resolution or accuracyfor location estimation around the location (x₊,y₊,z₊). A signaturefunction SF( ) may be defined utilizing metrics such as, for example,full channel response, RSSI, strongest multipath and/or angle of arrival(AoA), as following:

SF( )=sum{∥H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j) }−H ₀ {j,i,f _(k,i) ^(j),w _(s,i) ^(j)}∥²} over {j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}  (2)

corresponding to full channel response based signature function. In thiscase channel responses may be compared coherently which includes bothamplitude and phase of channel measurements.

SF( )=sum{∥H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}∥² −∥H ₀ {j,i,f _(k,i)^(j) ,w _(s,i) ^(j)}∥²} over {j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}  (3)

corresponding to RSSI based signature function.

SF( )=sum{max∥H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}∥²−max∥H ₀ {j,i,f_(k,i) ^(j) ,w _(s,i) ^(j)}∥²} over {j,i,f _(k,i) ^(j) ,w _(s,i)^(j)}  (4)

corresponding to strongest-multipath based signature function.

SF( )=AoA(H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)},H{j,i,f_(k,i) ^(j) ,w_(s,i) ^(j)}) over {j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}  (5)

corresponding to angle-of-arrival based signature function. In the aboveequation (5), the AOA( ) function may be utilized to calculate theangle-of-arrival difference between the channel measurementsH{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} and H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}in the cases where an antenna array at the receiver side may beavailable, that is, when the mobile device deploys an antenna array orwhen the base stations with antenna arrays are performing the channelmeasurements.

SF( )=sum{abs(TDOA(H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)})−TDOA(H ₀ {j,i,f_(k,i) ^(j) ,w _(s,i) ^(j)}))} over {j,i,f _(k,i) ^(j) ,w _(s,i)^(j)}  (6)

corresponding to time-difference-of-arrival (TDOA)-based signaturefunction. In the above equation (6), the TDOA( ) function may beutilized to calculate the time-difference between the arrival ofreceived corresponding multipaths within measured channel responsesH{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. The above time-difference may becalculated as the difference between the first and second strongestpaths within each channel response. In more general case, the timedifference may be calculated between the first path and second, betweenthe second and third, and so forth.

In all above descriptions, ∥.∥² is the Euclidean complex amplitude of aset of vectors (i.e., a matrix). In general, each element of channelmeasurement (H, H₀) may be a complex number with phase and amplitude.

SF( )=sum{∥abs(H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)})−abs(H ₀ {j,i,f_(k,i) ^(j) ,w _(s,i) ^(j)})∥²} over {j,i,f _(k,i) ^(j) ,w _(s,i)^(j)}  (7)

where abs( ) represents the magnitude function. Equation (7) correspondsto full channel response based signature function but the channelresponses may be compared incoherently which includes only amplitude ofchannel measurements.

In the above signature function variations, a time-alignment process maybe applied to channel response measurements collected during scanningand positioning phases. The purpose of this process is to align andcompensate for differences between the timers of scanning device (usedduring scanning phase) and the mobile device (being located). In oneconfiguration, the base stations are all considered synchronized intime. In this case, only a time-alignment between the scanning deviceand mobile device is required (base stations are synchronized in time).To implement this, a subset of channel response measurements may be usedby the location server to estimate the timers' difference between thescanning and mobile devices. For example, the location server 500analyzes a few of channel measurements corresponding to a subset oftransmit diversity configurations. By evaluating the first/strongestarriving element of channel response (first multipath) between thescanning and location phases, the location server 500 may then align allthe measured channel responses to compensate for such time or timers'difference. In another configuration where the base stations are notsynchronized in time, the above time alignment is repeated and appliedseparately to channel measurements corresponding to every base station.Therefore, the time or timers' difference between the device and eachbase station is compensated or accounted for, separately.

In one embodiment, as a different method, the task of synchronizingmeasurements between the scanning and mobile devices may be combinedinto the signature function minimization criterion. In an exemplaryoperation, the SF{ } operation in equation (2) may be modified asfollows:

SF( )=sum{∥H{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}(t−τ)−H ₀ {j,i,f _(k,i)^(j) ,w _(s,i) ^(j)}(t)∥²} over {j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}  (8)

where H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}(t) represents the channelmeasurement (from scanning phase) in time domain and H{j,i,f_(k,i)^(j),w_(s,i) ^(j)}(t) represents the channel measurement (from mobiledevice being located). The parameter (τ) represents the time differencebetween the timers of scanning and mobile devices. In a jointoptimization method, the above SF{ } is minimized over {j,i,f_(k,i)^(j),w_(s,i) ^(j)} and parameter(τ). Therefore, the minimization processmay find the best value for (τ) that may re-align the channelmeasurements to the best possible (hence minimizing the differencebetween H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} and H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}. Other SF{ } function may be similarly modified to include theabove synchronization method.

In some embodiments related to SF{ } in equations (2)-(4), a “weightedsum” is used to combine the values corresponding to {j,i,f_(k,i)^(j),w_(s,i) ^(j)} configurations. In an exemplary operation, thelocation server 500 may utilize a set of scaling factors α{j,i,f_(k,i)^(j),w_(s,i) ^(j)} where these scaling factors model the relativereliability and contribution of the channel measurements per eachtransmit diversity configuration. For example, for j valuescorresponding to base stations that are identified to be closer to themobile device (during coarse estimation), the corresponding α valueswould take a larger relative value. Similarly, for measurementscorresponding to high carrier frequencies, larger scaling factors may beused when a small region is being scanned (since higher carrierfrequencies provide better resolution over limited smaller regions).According to this embodiment, Equation (2) may be modified and used asfollows:

SF( )=sum{α{j,i,f _(k,i) ^(j) ,w _(s,i) ^(j) }×∥H{j,i,f _(k,i) ^(j) ,w_(s,i) ^(j) }−H ₀ {j,i,f _(k,i) ^(j) ,w _(s,i) ^(j)}∥²} over {j,i,f_(k,i) ^(j) ,w _(s,i) ^(j)}  (2-b)

Equation (2-b) corresponds to a full channel response based signaturefunction with unequal scaling factors.

It may be also possible to do channel measurement for the same frequencywith different waveforms or modulations. For example, Bluetooth andWi-Fi both may use the 2.4 GHz frequency spectrum. This is yet anotherdimension for channel measurements. The scaling factor α may also beapplied to such channel measurements based on their reliability. Forexample, Bluetooth may be given a smaller weight compared to Wi-Fi.

In an embodiment of the invention, the location accuracy and positionestimation error may be calculated for one or more subsets of thechannel measurements at scanned locations (x,y,z)εR_(s), H{j,i,f_(k,i)^(j),w_(s,i) ^(j)}, instead of using the entire parameter indices. Forexample, instead of using H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} for theentire of i=1, . . . , N within the base stations BS_(j), j=1, . . . ,M, the database processing engine 503 may utilize a subset or portion ofi=1, . . . , N_(j) transceivers for calculating signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})and consequently the location estimation resolution or error. The aboveprocess may be applied to various combinations to sort the positioningdatabase 504 in terms of estimation resolution and error. In instanceswhere it is identified that adding an element from the positioningdatabase 504 to the channel measurements at scanned locations(x,y,z)εR_(s), H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} used forSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})calculation doesn't improve the resolution or accuracy above a target orprogrammable threshold, that element may be eliminated or removed fromthe set used for positioning around a particular location point such as(x₊,y₊,z₊)εR_(s). For example, assume using antenna phase arraycoefficients of w_(s,i) ^(j) doesn't improve the location accuracy orerror by a programmable threshold, then the antenna phase arraycoefficients of w_(s,i) ^(j) may not be utilized for positioning themobile device in region R_(s) to simplify the positioning and make themeasurements collection faster. Similar filtering may be applied toother variables such as carrier frequencies used (f_(k,i) ^(j)), basestations used (j), and transceivers used (i).

In an embodiment of the invention, a filtering method may be used tosort or reduce the number of required configurations. For example,consider a sub-region R′_(s), the location server 500 may analyze allthe measurements collected for this region during the scanning phase andidentify the transmit diversity configurations that do not contributesubstantially to the location accuracy in the region R′_(s). For thistask, the location server 500 may utilize the following procedure.First, the location server 500 may analyze the data collected from thescanning phase. Second, the location server 500 may take a singlescanned location in the region R′_(s), say (x₊,y₊,z₊) R′_(s). Next, theserver 500 may calculate SF(H{j,i,f_(k,i) ^(j),w_(s,i)^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}) versus all scanned locations(x,y,z)εR′_(s) with respect to location (x₊,y₊,z₊)εR′_(s). In otherwords, H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}, corresponds to scanned channelmeasurements for location (x₊,y₊,z₊)εR′_(s) where H{j,i,f_(k,i)^(j),w_(s,i) ^(j)} corresponds to scanned channel measurements for allother locations in (x,y,z)εR′_(s). By definition, the SF{ } valuescalculated will be minimum (i.e., zero) at location (x₊,y₊,z₊) and maygradually increase for points in (x,y,z)εR′_(s) as they are further from(x₊,y₊,z₊). The slope of this increase may be a measure of locationaccuracy/resolution achievable around point (x₊,y₊,z₊) when SF{ } isused and all configurations are utilized. The above accuracy may be thebest achievable with SF{ } at location (x₊,y₊,z₊) or region R′_(s) whenall collected configurations are deployed. The location server 500 maystore the result of the above analysis as accuracy that is achievablewith this specific SF{ } and at region R′_(s) when all configurationsj=1, . . . , M; i=1, . . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), . . . ,f_(K) _(j) _(,i) ^(j); w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j)are utilized. In the next step, the location server 500 may repeat theabove process except for a subset of configurations j=1, . . . , M; i=1,. . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i) ^(j);w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j) and stores the accuracyfor that particular subset of configurations. At the end of the aboveprocedure, the location server 500 may have a table for each sub-regionR′_(s) assigning achievable accuracy to each subset of j=1, . . . , M;i=1, . . . , N_(j); f_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i)^(j); w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j) configurations.The location server 500 may then utilize the above table for decidingwhat subset of configurations to utilize when positioning a mobiledevice. For example, once the location server 500 determines that themobile device is in the sub-region R′_(s) through some initial coarseestimation, the location server 500 may identify and use the matchingtable for that sub-region. Within the corresponding tables, the locationserver 500 then search for the desired accuracy requirements. The tablemay return a group of possible subsets of configurations that result inthe required accuracy requirements. The location server 500 then picksthe satisfying subset based on some other criterions (such as powerconsumption, number of measurements, number of base stations, etc.). Forexample, the location server 500 may pick the subset of configurationsthat has the least elements, which translates to the minimum number ofchannel measurements for the device (resulting in fastest or mostefficient estimation process). The above process to create and populatethe tables by the location server may be performed offline after thescanning measurements are collected so that the tables are readilyavailable during the positioning of mobile devices.

In another embodiment, the above tables for each sub-region R′_(s) maybe repeated for a variety of SF{ } definitions. This may add anadditional dimension to the tables; the SF{ } definition. Consequently,for a desired location accuracy in the sub-region R′_(s), the locationserver 500 may pick the sub-set of configurations and the SF{ } based onother criterions such as minimizing the number of channel measurements.

In an embodiment of the invention, positioning configuration informationmay be stored by the database processing engine 503 for future use. Thepositioning configuration information may comprise various positioningfiltering schemes or positioning scanning settings such as, for example,different SF( ) definitions, SF( ) accuracy or error associated withscanned locations (x,y,z)εR_(s) for different subsets of {j,i,f_(k,i)^(j),w_(s,i) ^(j)}, elements that do not improve the SF( )accuracy/slope/error within a subset of {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}for different SF( ) definitions, and different location scanning regionsR_(s). For example, using the stored positioning filtering schemes orpositioning scanning settings, the number of antenna phase arraycoefficients of w_(s,i) ^(j)=w_(1,i) ^(j), . . . , w_(S,i) ^(j) neededto conduct measurements of H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} andH₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} may be greatly reduced. This mayresult in less number of measurements with minimal degradation in devicepositioning. In some cases, according to the stored positioningconfiguration information during database processing, the databaseprocessing engine 503 may utilize a limited number such as one ofw_(1,i) ^(j), . . . , w_(S,i) ^(j) for the i^(th) transceiver within thebase stations BS_(j), j=1, . . . , M, for each scanned location point(x,y,z)εR_(s). For example, the single one of w_(1,i) ^(j), . . . ,w_(S,i) ^(j) may correspond to the antenna phase coefficients thatcreate the best path or the best reflection from the i^(th) transceiverto the device being located such as the multi-radio mobile device 112.

In some instances, matching and/or minimizing a single unified SF( )definition of measurement data, H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} andH₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}, for the device to be located againstthe entire possible locations within the location scanning region R_(s)may not yield a reliable or unique solution. Certain SF( ) definitions,however, may yield a very good resolution only over a subspace R′_(s)within the location scanning region R_(s). A brute-force calculation andcomparison of various SF( ) definitions against the entire locationswithin the location scanning region R_(s) may lead to multiple locationestimates that correlate with the positioning database 504 with theminimum values of the corresponding SF( ) definitions in the locationscanning region R, for the device to be located. In this regard, thevariety of SF definitions that are available and applicable within thelocation scanning region R_(s) utilized in the positioning database 504may be limited for device positioning.

In an embodiment of the invention, the database processing engine 503may utilize or perform multi-level positioning for highly accuratepositioning. In this regard, the database processing engine 503 mayutilize a coarse positioning method such as a GPS-based positioning orcoarse angle-of-arrival method to establish or select an initialestimate for the subspace R′_(s) the location scanning region R_(s) forthe mobile device to be located. The subspace R′_(s)⊂R_(s) correspondsto a boundary or range within the location scanning region R_(s) wherelocation scanning may be performed effectively to locate the device tobe located. Once subspace R′_(s) identified, the database processingengine 503 may estimate the position for the device to be located bymatching or correlating measurement data, H{j,i,f_(k) ^(j),w_(i) ^(j)}and H₀{j,i,f_(k) ^(j),w_(i) ^(j)}, utilizing higher resolution SF( )only in the subspace R′_(s)⊂R_(s), but not the entire location scanningregion R_(s). The resulting location estimation for the device to belocated may be utilize to refine the selection of the subspaceR′_(s)⊂R_(s), for example, by reducing choosing a smaller sized subspaceR″_(s)⊂R′_(s)⊂R_(s) for subsequent location estimate for the device tobe located by using a different higher resolution SF( ) definition. Inan embodiment of the invention, same set of scanned locations(x,y,z)εR_(s) may be re-visited for new set of channel transmitdiversity configurations, {j,i,f_(k) ^(j),w_(i) ^(j)}, and possible newSF( ) definitions for subsequent finer location estimation for thedevice to be located. The multi-level positioning process may bebasically repeated until the resolution requirements are met.

In one embodiment, the same method and database is utilized to performthe coarse initial location estimation. The initial coarse estimation isachieved by using only a subset of transmit diversity configurations{j,i,f_(k) ^(j),w_(i) ^(j)} and SF{ } that are identified to provide lowpositioning accuracy but full coverage over the region R_(s). In anexemplary operation, the configurations with low carrier frequenciesf_(k,i) ^(j) are selected for coarse initial positioning whereasconfigurations with higher carrier frequencies are used in next levelsof positioning. In another exemplary operation, the base stations mayhave radio capability of operating at both WLAN channels (2.4 GHz and 5GHz carrier frequencies) as well as mmWave channels (60 GHz carrierfrequencies). This capability may be implemented through use of separateradios (one for WLAN operation and another for mmWave operation) or anintegrated single radio covering all 2.4/5/60 GHz bands. In this case,configurations with f_(k,i) ^(j) around 2.4/5 GHz are used to estimateinitial location of the mobile device. Such lower frequencies areexpected to provide less resolution but cover a large region. Once thisinitial estimate is completed and a finer region for the mobile deviceis estimated, configurations with f_(k,i) ^(j) around 60 GHz are usedfor higher resolution estimation in accordance to other embodiments.

The multi-level positioning process may enable the use of higherresolution SF( ) definitions as well as eliminating ambiguity inpinpointing location. For example, once a coarse location estimatewithin the location scanning region R_(s) is determined for the deviceto be located such as the multi-radio mobile device 112, the databaseprocessing engine 503 may look into the positioning database 504 for asubspace R′_(s)⊂R_(s). The database processing engine 503 may specify orselect a sub-set of channel transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} suitable for positioning within thesubspace R′_(s)⊂R_(s). For example, given the location estimationaccuracy target, the database processing engine 503 identifies orselects only a set of two base stations, for example, BS₁ and BS₃, whichmay be sufficient to provide a location estimate for the device to belocated. Assume that within the base station BS₁, the databaseprocessing engine 503 may choose the transceiver i=2 with antennacoefficients w_(s=1,i=2) ^(j=1) and w_(s=2,i=2) ^(j=1), choose thetransceiver i=4 with antenna coefficients w_(s=1,i=4) ^(j=1) at carrierfrequencies f_(k=1,i=4) ^(j=1) and f_(k=2,i=4) ^(j=1), and so forth. Thebase stations BS₁ and BS₃ may be instructed to conduct correspondingchannel measurements either in parallel or sequential. Once the set ofchannel measurements H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} are collected,then the database processing engine 503 may calculate the SF( ) againstall location points within the subspace R′_(s)⊂R_(s) in the positioningdatabase 504. The database processing engine 503 may consider theminimum value of the SF( ) calculated within the subspace R′_(s)⊂R_(s)as a final indicator for location estimate. The above process may berepeated or continued for finer resolution. For example, a subsequentlocation estimation may be used to define or select a smaller locationscanning region R″_(s), where R″_(s)⊂R′_(s)⊂R_(s). In another example,the positioning database 504 may be re-visited for a new set of transmitdiversity configurations and possible new SF( ) definitions for nextfiner location estimation.

The positioning database 504 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to manage and/or store datacomprising channel measurements H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} learnedfrom a plurality of associated radio sites such as base stations and/orAPs. The contents in the positioning database 504 may be updated asneeded, either aperiodically or periodically.

The memory 506 may comprise suitable logic, circuitry, interfaces and/orcode that may be operable to store information comprising executableinstructions, and configuration information, that may be utilized by theprocessor 502. The executable instructions may comprise algorithms thatmay be utilized to calculate location estimate for mobile devices usingbase stations with distributed transceivers through array processing.The memory 506 may comprise RAM, ROM, low latency nonvolatile memorysuch as flash memory and/or other suitable electronic data storage.

In an exemplary operation, the processor 502 may be operable to collector track location related information of associated mobile devices tobuild the positioning database 504. Radio sites such as the basestations BS_(j), j=1, . . . , M, each with i=1, . . . , N_(j)distributed transceivers may be utilized by the database processingengine 503 for device positioning. In this regard, the databaseprocessing engine 503 may determine transmit diversity configurationsand instruct the base stations BS_(j), j=1, . . . , M, to conductcorresponding channel measurements. Various SF( ) definitions such asfull channel response-based SF( ) definition may be selected for thechannel measurements over a location scanning region R_(s). Amulti-level positioning process may be performed utilizing thepositioning database 504 for highly accurate positioning.

FIG. 6 is a diagram illustrating exemplary steps utilized by a locationserver to perform device positioning utilizing distributed transceiverswith array processing, in accordance with an embodiment of theinvention. Referring to FIG. 6, in step 602, a location server 500utilizes multiple distributed transceivers with antenna array processingfor device positioning. The exemplary steps start with step 604, wherethe database processing engine 503 may be operable to select a locationscanning region R_(s) for a device to be located, for example, themulti-radio mobile device 112. The location scanning region R_(s) forthe device to be located may be selected or identified utilizing variouscoarse positioning methods such as a GPS-based positioning method or acoarse angle-of-arrival based positioning. The location scanning regionR_(s) is covered or served by a plurality of base stations BS_(j), j=1,. . . , M, each with multiple distributed transceivers, i=1, . . . ,N_(j). Each of the N_(j) distributed transceivers for the base stationBS_(j) may be equipped with an independently configurable antenna array.Each of the N_(j) distributed transceivers may operate at differentcarrier frequencies f_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i)^(j).

In step 606, the database processing engine 503 may be operable todetermine channel transmit diversity configurations, {j,i,f_(k,i)^(j),w_(s,i) ^(j)}, for the distributed transceivers of the basestations BS_(j), j=1, . . . , M. The determined channel transmitdiversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} may comprisevarious channel transmit settings such as, for example, radio siteidentifier index, transceiver index, transceiver operating frequency,and transmit antenna patterns (array coefficients) and arrayconfigurations.

In step 608, during the scanning phase, the processor 502 may instructor signal each of the base stations BS_(j), j=1, . . . , M, to conduct aset of channel measurements H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} accordingto the determined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)} at each scanned location point in the locationscanning region R_(s). In step 610, during the positioning phase, theprocessor 502 may instruct each of the base stations to conduct channelmeasurements for the mobile device to be located according to thedetermined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)}. In step 612, the processor 502 may be operable toretrieve the channel measurements associated with each of the scannedlocations in the location scanning region R_(s), and the channelmeasurements for the device to be located in accordance with thedetermined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)}. In step 614, the database processing engine 503 mayselect a signature function SF( ) for the collected channelmeasurements, H{ } and the scanning phase channel measurements H₀{ },over the determined channel transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. In this regard, the signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})may be defined utilizing various metrics such as, for example, fullchannel response, RSSI, strongest multipath and/or angle of arrival(AoA), as presented in equations (2) through (5). In step 616, thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) may be utilized to estimate the position for thedevice over the determined transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} at each scanned location point in thelocation scanning region R_(s).

FIG. 7 is a diagram illustrating exemplary steps utilized by a locationserver to perform multi-level device positioning utilizing a subset ofchannel transmit diversity configurations, in accordance with anembodiment of the invention. Referring to FIG. 7, in step 702, alocation server 500 utilizes multiple distributed transceivers withantenna array processing for device positioning. The exemplary stepsstart with step 704, where the database processing engine 503 may beoperable to select a location scanning region R, for a device to belocated, for example, the multi-radio mobile device 112. The locationscanning region R_(s) for the device to be located may be selected oridentified utilizing various coarse positioning methods such as aGPS-based positioning method or coarse WLAN-based positioning method.The location scanning region R_(s) is covered or served by a pluralityof base stations BS_(j), j=1, . . . , M, each with multiple distributedtransceivers, i=1, . . . , N_(j). Each of the N_(j) distributedtransceivers for the base station BS_(j) may be equipped with anindependently configurable antenna array. Each of the N_(j) distributedtransceivers may operate at different carrier frequencies f_(k,i)^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i) ^(j).

In step 706, the database processing engine 503 may be operable todetermine channel transmit diversity configurations, {j,i,f_(k,i)^(j),w_(s,i) ^(j)}, for the distributed transceivers of the basestations BS_(j), j=1, . . . , M. The determined channel transmitdiversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} may comprisevarious channel transmit settings such as, for example, radio siteidentifier index, transceiver index, transceiver operating frequency,and transmit antenna patterns and array configurations. In step 708, thedatabase processing engine 503 may select a subset of the determinedchannel transmit diversity configurations for the distributedtransceivers of the base stations BS_(j), j=1, . . . , M. For example, asubset or portion of i=1, . . . , N_(j) transceivers and/or carrierfrequencies f_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i) ^(j) maybe selected to be used for conducting channel measurements H{j,i,f_(k,i)^(j),w_(s,i) ^(j)} instead of using the entire parameter indices. Thissub-set selection may or may not be considered during the positioning ofthe mobile device (i.e., location estimation phase). During thescanning, all available transmit diversity configurations may beprogrammed and all corresponding channel measurements may be collectedinto the server database.

In step 710, the processor 502 may instruct or signal each of the basestations BS_(j), j=1, . . . , M, to conduct a set of channelmeasurements H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} according to the subset ofthe determined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)} at each scanned location point in the locationscanning region R_(s). Step 710 may be bypassed in order to keep thescanning phase measurements as complete as possible. In step 712, theprocessor 502 may instruct each of the base stations to conduct channelmeasurements for the mobile device to be located according to the subsetof the determined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)}. In step 714, the processor 502 may be operable tocollect or retrieve the channel measurements associated with each of thescanned locations in the location scanning region R_(s), and the channelmeasurements for the device to be located in accordance with the subsetof the determined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)}.

In step 716, the database processing engine 503 may select a signaturefunction SF( ) which may vary from iteration to iteration based on:accuracy resolution from previous iteration, target resolution accuracy,and the updated region of the mobile device, for the collected channelmeasurements, H{ } and H₀{ }, over the subset of the determined channeltransmit diversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. Inthis regard, the signature function SF(H{j,i,f_(k,i) ^(j),w_(s,i)^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}) may be defined utilizingvarious metrics such as, for example, full channel response, RSSI,strongest multipath and/or angle of arrival (AoA), as presented inequations (2) through (5). In step 718, the database processing engine503 may check or evaluate resolution capability of the signaturefunction SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}) by calculating the slop or the gradient of the signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})versus each of the scanned locations in the location scanning regionR_(s). In instances where the resolution capability of the signaturefunction SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}) satisfies a particular accuracy requirement, then the exemplarysteps continue in step 720, where the signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})may be utilized to estimate the position for the device to be locatedover the subset of the determined channel transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} at each scanned locationpoint in the location scanning region R_(s).

In step 718, in instances where the resolution capability of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) does not satisfy the accuracy requirements, then theexemplary steps continue in step 710 and/or in step 716 depending onsystem configuration. In this regard, the resolution capability of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) may be improved by selecting a different signaturefunction SF( ) and/or selecting a different subset of the determinedchannel transmit diversity configurations {j,i,f_(k,i) ^(j),w_(s,i)^(j)} to repeat the database processing until the accuracy requirementsare met.

FIG. 8 is a diagram illustrating exemplary steps utilized by a locationserver to perform multi-level device positioning over a subset of alocation scanning region, in accordance with an embodiment of theinvention. Referring to FIG. 8, in step 802, a location server 500utilizes multiple distributed transceivers with antenna array processingfor device positioning. The exemplary steps start with step 804, wherethe database processing engine 503 may be operable to select a locationscanning region R_(s) for a device to be located, for example, themulti-radio mobile device 112. The location scanning region R_(s) forthe device to be located may be selected or identified utilizing variouscoarse positioning methods such as a GPS-based or WLAN-based positioningmethod. The location scanning region R_(s) is covered or served by aplurality of base stations BS_(j), j=1, . . . , M, each with multipledistributed transceivers, i=1, . . . , N_(j). Each of the N_(j)distributed transceivers for the base station BS_(j) may be equippedwith an independently configurable antenna array. Each of the N_(j)distributed transceivers may operate at different carrier frequenciesf_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i) ^(j).

In step 806, the database processing engine 503 may be operable todetermine channel transmit diversity configurations, {j,i,f_(k,i)^(j),w_(s,i) ^(j)}, for the distributed transceivers of the basestations BS_(j), j=1, . . . , M. The determined channel transmitdiversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} may comprisevarious channel transmit settings such as, for example, radio siteidentifier index, transceiver index, transceiver operating frequency,and transmit antenna patterns and array configurations. In step 808, thedatabase processing engine 503 may select a subspace R′_(s) the locationscanning region R_(s). For example, a set of particular location pointsaway from the boundaries of the location scanning region R_(s) may beselected to form the subspace R′_(s)⊂R_(s). In one embodiment, step 808may be bypassed as the scanning phase is conducted for the entire regionof interest.

In step 810, the processor 502 may instruct or signal each of the basestations BS_(j), j=1, . . . , M, to conduct a set of channelmeasurements H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} according to thedetermined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)} at each scanned location point in the subspaceR′_(s)⊂R_(s). In step 812, the processor 502 may instruct each of thebase stations to conduct channel measurements for the device to belocated according to the determined channel transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. In step 814, theprocessor 502 may be operable to collect or retrieve the channelmeasurements associated with each of the scanned locations in thesubspace R′_(s)⊂R_(s), and the channel measurements for the device to belocated in accordance with the determined channel transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}.

In step 816, the database processing engine 503 may select a signaturefunction SF( ) for the collected channel measurements, H{ } and H₀{ },over the determined channel transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. In this regard, the signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})may be defined utilizing various metrics such as, for example, fullchannel response, RSSI, strongest multipath and/or angle of arrival(AoA), as presented in equations (2) through (5). The choice of SF{ }may vary from one iteration to next depending on the updated estimate ofregion R″_(s) of the mobile device and target location resolution. Asthe region R″_(s) gets finer and smaller over iterations, SF{ }functions are selected that are more suitable for higher resolution butonly work over a smaller region. In step 818, the database processingengine 503 may check or evaluate resolution capability of the signaturefunction SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}), for example, by calculating the slop or the gradient of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) versus each of the scanned locations in the subspaceR′_(s)⊂R_(s). In instances where the resolution capability of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) satisfies accuracy requirements, then the exemplarysteps continue in step 820, where the signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})may be utilized to estimate the position for the device over thedetermined channel transmit diversity configurations {j,i,f_(k,i)^(j),w_(s,i) ^(j)} at each scanned location point in the subspaceR′_(s)⊂R_(s).

In step 818, in instances where the resolution capability of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) does not satisfy the accuracy requirements, then theexemplary steps continue in step 808. In step 808, the databaseprocessing engine 503 may select a different subspace R″_(s) (finer andsmaller than the previous one using the not-sufficiently-accuratelocation estimate from this iteration) of the location scanning regionR_(s). For example, R″_(s)⊂R′_(s)⊂R_(s) may be selected and the databaseprocessing may be repeated until the accuracy requirements are met.

Aspects of a method and system for device positioning utilizingdistributed transceivers with array processing and database processingare provided. In accordance with various exemplary embodiments of theinvention, as described with respect to FIG. 1 through FIG. 8, a mobilecommunication device such as the multi-radio mobile device 400 in amultipath environment 200 may be operable to multipath receive radiofrequency signals from one or more radio sites such as the base stationsBS_(j), j=1, . . . , M, each with multiple distributed transceivers,i=1, . . . , N_(j). Each of the distributed transceivers i=1, . . . ,N_(j) may be configured to operate at different carrier frequenciesf_(k,i) ^(j)=f_(1,i) ^(j), . . . , f_(K) _(j) _(,i) ^(j). Each of theN_(j) distributed transceivers for the base station BS_(j) be equippedwith an independently configurable antenna array for transmitting theradio frequency signals to the multi-radio mobile device 400, where,w_(1,i) ^(j), . . . , w_(S,i) ^(j) represent the phase arraycoefficients of the i^(th) transceiver for the base stations BS_(j),i=1, . . . , N_(j); j=1, . . . , M.

The host processor 414 of the multi-radio mobile device 400 may processthe received signals to generate channel measurements such as, forexample, channel response or RSSIs, for the received signals. A remotelocation server such as the location server 500 may be operable tolocate the multi-radio mobile device 400 utilizing the channelmeasurements for the multi-radio mobile device 400. In this regard,corresponding transmit diversity configurations may be determined by thelocation server 500. The corresponding transmit diversity configurationsmay be applied to the base stations BS_(j), j=1, . . . , M, forconducting the channel measurements for the multi-radio mobile device400, and channel measurements at each scanned location in the locationscanning region R_(s). The position estimate for the multi-radio mobiledevice 400 may be calculated by the location server 500 over thelocation scanning region R_(s) utilizing the channel measurements forthe multi-radio mobile device 400, the channel measurements at scannedlocations, and corresponding transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}, which comprise base station identifierindex, transceiver index, transceiver operating frequency, and transmitantenna patterns and array configurations for each of the base stationsutilized for positioning the multi-radio mobile device 400.

In an exemplary embodiment of the invention, the location server 500 mayselect a signature function SF(H{j,i,f_(k,i) ^(j),w_(s,i)^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}) for the channel measurementsfor the multi-radio mobile device 400, and the channel measurements withthe scanned locations over the corresponding transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. The signature functionSF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)})may be defined utilizing various metrics such as, for example, fullchannel response, RSSI, strongest multipath and/or angle of arrival(AoA), as presented in equations (2) through (5). The location server500 may utilize the signature function SF(H{j,i,f_(k,i) ^(j),w_(s,i)^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}) to calculate or determine theposition estimate({circumflex over (x)},ŷ,{circumflex over (z)}) for themulti-radio mobile device 400 over the transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)}. Depending on resolution of thesignature function SF( ) over the scanned locations in the locationscanning region R_(s), the location server 500 may perform multi-levelpositioning process for highly accurate positioning. In this regard, thedatabase processing engine 503 may check resolution of the signaturefunction SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i) ^(j),w_(s,i)^(j)}), for example, by calculating the slope or the gradient of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) versus each of the scanned locations in the locationscanning region R_(s). In instances where the resolution of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) does not satisfy the accuracy requirements, then theposition estimate({circumflex over (x)},ŷ,{circumflex over (z)}) for themulti-radio mobile device 400 may be updated. For example, the databaseprocessing engine 503 may utilize a different signature function SF( )to calculate the updated position estimate({circumflex over(x)},ŷ,{circumflex over (z)}) for the multi-radio mobile device 400 overthe transmit diversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)}.

In addition, a subset of the channel transmit diversity configurations{j,i,f_(k,i) ^(j),w_(s,i) ^(j)} and/or a subspace of the locationscanning region R_(s) corresponding to higher resolution of thesignature function SF(H{j,i,f_(k,i) ^(j),w_(s,i) ^(j)},H₀{j,i,f_(k,i)^(j),w_(s,i) ^(j)}) may be identified or selected by the databaseprocessing engine 503. To simplify the device positioning, the databaseprocessing engine 503 may select a subset of the transmit diversityconfigurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} and/or a subspace of thelocation scanning region R_(s) over which the signature function SF( )yields a very good resolution. The database processing engine 503 mayutilize the signature function SF( ) to calculate the updated positionestimate ({circumflex over (x)},ŷ,{circumflex over (z)}) for themulti-radio mobile device 400 over the selected subset of the transmitdiversity configurations {j,i,f_(k,i) ^(j),w_(s,i) ^(j)} and/or thescanned locations in the selected subspace of the location scanningregion R_(s). The multi-radio mobile device 400 may receive the updatedposition estimate from the database processing engine 503 to supportLBSs.

In one embodiment, if strong stationary reflectors are identified in theenvironment or strong passive/active reflectors are installed in theenvironment with known locations (in accordance to another embodiment),the location server 500 may choose antenna array coefficients w_(1,i)^(j), . . . , w_(S,i) ^(j) for each base station and transceiver suchthat the resulting antenna beam patterns would point to the strongnatural/installed reflectors in the room. In the case of installedreflectors, since the location of base station and location ofreflectors are known by the location server 500, the location server 500may use that information to derive w_(1,i) ^(j), . . . , w_(S,i) ^(j)coefficients that results in strong multipath through a pointed antennapattern between the base station and those strong reflectors. Multipathsthat are caused by reflectors may create virtual transmitter basestations. For example, in FIG. 2, the base station 222 transmits radiowaves 231, which reflect from reflector 241 as 231 a and arrive atmobile device 210. The multipath 231-231 a may be viewed as originatingfrom a virtual base station, where the position of this virtual basestation is the reflection of base station 222 on the wall of reflector241. This position intersects the straight line 231 a when line 231 a isextended backwards. Likewise, the reflectors 242, 243, and 244 maycreate virtual base stations. The greater the number of reflectors thegreater is the number of virtual transmitters and that translates into ahigher accuracy for the positioning method of this invention. This is insharp contrast to conventional methods, where multipath propagationdegrades system performance.

Other embodiments of the invention may provide a non-transitory computerreadable medium and/or storage medium, and/or a non-transitory machinereadable medium and/or storage medium, having stored thereon, a machinecode and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for devicepositioning utilizing distributed transceivers with array processing anddatabase processing.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A method of processing signals, the method comprising: in a mobiledevice: receiving radio frequency signals from one or more basestations, wherein: each of said one or more base stations comprises aplurality of distributed transceivers; and each of said plurality ofdistributed transceivers comprises an independently configurable antennaarray for transmitting said radio frequency signals to said mobiledevice; generating channel measurements for said received radiofrequency signals; and receiving a position estimate for said mobiledevice from a remote location server, wherein: corresponding transmitdiversity configurations are determined by said remote location server,said corresponding transmit diversity configurations being applied tosaid one or more base stations for both said channel measurements forsaid mobile device and channel measurements at scanned locations in alocation scanning region; and said position estimate for said mobiledevice over said location scanning region utilizing said channelmeasurements for said mobile device, said channel measurements at saidscanned locations, and said corresponding transmit diversityconfigurations are calculated by said remote location server.
 2. Themethod according to claim 1, wherein said corresponding transmitdiversity configurations comprise base station identifier index,transceiver index, transceiver operating frequency, and transmit antennapatterns and array configurations for each of said one or more basestations.
 3. The method according to claim 1, wherein a signaturefunction for said channel measurements for said mobile device, and saidchannel measurements at said scanned locations over said correspondingtransmit diversity configurations, are selected by said remote locationserver.
 4. The method according to claim 3, wherein said signaturefunction is defined in terms of full channel response, receive signalstrength indicator, strongest multipath, or angle of arrival for saidchannel measurements for said mobile device, and said channelmeasurements at said scanned locations over said corresponding transmitdiversity configurations.
 5. The method according to claim 3, whereinsaid signature function is utilized by said remote location server todetermine said position estimate for said mobile device over saidcorresponding transmit diversity configurations.
 6. The method accordingto claim 5, wherein said position estimate for said mobile device isupdated by said remote location server based on resolution of saidsignature function over said scanned locations in said location scanningregion.
 7. The method according to claim 6, wherein a subset of saidcorresponding transmit diversity configurations and/or a subspace ofsaid location scanning region is selected by said remote location serverbased on said resolution of said signature function over said scannedlocations in said location scanning region.
 8. The method according toclaim 7, wherein said signature function is utilized by said remotelocation server to calculate said updated position estimate for saidmobile device over said subset of said corresponding transmit diversityconfigurations and/or over said subspace of said location scanningregion.
 9. The method according to claim 6, wherein said updatedposition estimate for said mobile device is calculated by said remotelocation server, by utilizing a different signature function for each ofsaid channel measurements for said mobile device and said channelmeasurements with said known locations over said corresponding transmitdiversity configurations.
 10. The method according to claim 6,comprising receiving said updated position estimate at said mobiledevice.
 11. A system for processing signals, the system comprising: amobile device, said mobile device being operable to: receive radiofrequency signals from one or more base stations, wherein: each of saidone or more base stations comprises a plurality of distributedtransceivers; and each of said plurality of distributed transceiverscomprises an independently configurable antenna array for transmittingsaid radio frequency signals to said mobile device; determine channelcharacteristics for said received radio frequency signals; generatechannel measurements for said received radio frequency signals; andreceive a position estimate for said mobile device from a remotelocation server, wherein: corresponding transmit diversityconfigurations are determined by said remote location server, saidcorresponding transmit diversity configurations being applied to saidone or more base stations for both said channel measurements for saidmobile device and channel measurements at scanned locations in alocation scanning region; and said position estimate for said mobiledevice over said location scanning region utilizing said channelmeasurements for said mobile device, said channel measurements at saidscanned locations, and said corresponding transmit diversityconfigurations are calculated by said remote location server.
 12. Thesystem according to claim 11, wherein said corresponding transmitdiversity configurations comprise base station identifier index,transceiver index, transceiver operating frequency, and transmit antennapatterns and array configurations for each of said one or more basestations.
 13. The system according to claim 11, wherein a signaturefunction for said channel measurements for said mobile device, and saidchannel measurements at said scanned locations over said correspondingtransmit diversity configurations, are selected by said remote locationserver.
 14. The system according to claim 13, wherein said signaturefunction is defined in terms of full channel response, receive signalstrength indicator, strongest multipath, or angle of arrival for saidchannel measurements for said mobile device, and said channelmeasurements at said scanned locations over said corresponding transmitdiversity configurations.
 15. The system according to claim 13, whereinsaid signature function is utilized by said remote location server todetermine said position estimate for said mobile device over saidcorresponding transmit diversity configurations.
 16. The systemaccording to claim 15, wherein said position estimate for said mobiledevice is updated by said remote location server based on resolution ofsaid signature function over said scanned locations in said locationscanning region.
 17. The system according to claim 16, wherein a subsetof said corresponding transmit diversity configurations and/or asubspace of said location scanning region is selected by said remotelocation server based on said resolution of said signature function oversaid scanned locations in said location scanning region.
 18. The systemaccording to claim 17, wherein said signature function is utilized bysaid remote location server to calculate said updated position estimatefor said mobile device over said subset of said corresponding transmitdiversity configurations and/or over said subspace of said locationscanning region.
 19. The system according to claim 16, wherein saidupdated position estimate for said mobile device is calculated by saidremote location server, by utilizing a different signature function foreach of said channel measurements for said mobile device, and saidchannel measurements with said known locations over said correspondingtransmit diversity configurations.
 20. The system according to claim 16,wherein said mobile device receives said updated position estimate.